using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;

namespace ServiceHelper
{
    public class QueryPerformance
    {
        [DllImport("Kernel32.dll")]
        private static extern bool QueryPerformanceCounter(out long performanceCount);

        [DllImport("Kernel32.dll")]
        private static extern bool QueryPerformanceFrequency(out long frequency);

        private  long begintTime = 0;//开始时间  

        private  long endTime = 0;//结束时间  

        private  long frequency = 0;//处理器频率  

        public long BegintTime
        {
            get { return begintTime; }
        }

        public long EndTime
        {
            get { return endTime; }
        }

        public long Frequency
        {
            get { return frequency; }
        }


        public QueryPerformance()  
        {
            QueryPerformanceFrequency(out frequency);//获取频率  
        }

        public void Start()
        {
            QueryPerformanceCounter(out begintTime);
        }

        public string Stop(bool showRecord)
        {
            QueryPerformanceCounter(out endTime);

            if (showRecord)
            {
                return string.Format("用时:{0}ms", TastTime);
            }
            return null;
        }

        public double TastTime//花费时间：单位S  
        {
            get
            {
                if (frequency > 0)
                    return (double)(endTime - begintTime)*1000 / frequency;
                else
                    return 0;
            }
        }  
    }
}